Natural sources of musk or musk-like odor have been prized in perfumery. In the fragrance industry, however, natural materials have largely been supplanted by readily available synthetics with musk-like odors. One of the most important commercial musks, the dinitro-material 1, below, was discovered by Baur nearly 100 years ago. However, because of questions concerning the safety of the nitro-musks, there is a need in the fragrance industry for new synthetic musks which can be used as replacements for the nitro-musks, especially the dinitro-material 1. ##STR2##
Many materials which possess a musk-like odor have been prepared by chemists over the years and are known to those skilled in the art. Much of the early work on synthetics is described in review articles by T. F. Wood in Givaudanian between 1968 and 1970. The preparation and must-like odor of napthodioxepins was reported by R. C. Cookson et al., J. Chem. Soc. (1976) 195-200. More recently, the chemistry of musk has been discussed in "Fragrance Chemistry; The Science of the Sense of Smell, edited by E. T. Thiemer (1982). In Thiemer's book, Chapter 12, an article by B. D. Mookheyee and R. A. Wilson, discusses natural musk materials and Chapters 13 and 14 by T. F. Wood discuss synthetic musk. Benzenoid must materials generally contain an electron-withdrawing substituent on the aromatic ring, such as a nitro, nitrile or carbonyl group.
Compounds 2 and 3 are the subjects of recent U.S. Pat. Nos. 4,476,040 and 4,483,786, respectively. ##STR3## wherein R.sup.1 is methyl or ethyl.
These known materials, however, have complex structures and/or are difficult to synthesize. In addition, questions concerning the safety of the commercially successful nitro-musks have created a need in the fragrance industry for synthetic replacements. Therefore, it is an object of the invention to prepare novel compounds that are devoid of nitro groups or other potentially hazardous functionality yet possesses a strong must note resembling in character the nitro-musk 1. Yet another object is to develop a compound that is synthetically easy to prepare.